Field of the Invention
The present invention relates to wireless communication and, more particularly, to a method for measuring and reporting a channel state information-reference signal (CSI-RS) in a wireless communication system and an apparatus for supporting the same.
Related Art
3GPP (3rd Generation Partnership Project) LTE (long term evolution) which is improvement of UMTS (Universal Mobile Telecommunications System) has been introduced as 3GPP release 8. The 3GPP LTE uses OFDMA (orthogonal frequency division multiple access) in a downlink, and uses SC-FDMA (Single Carrier-frequency division multiple access) in an uplink. The 3GPP LTE adopts MIMO (multiple input multiple output) having maximum four antennas. Recently, a discussion of 3GPP LTE-A (LTE-Advanced) which is the evolution of the 3GPP LTE is in progress.
In recent years, with the supply of smart phones, a request of a user wanting to receive a data service having a high level of quality regardless of time and location has been increased. Accordingly, there is a need capable of supporting high data rate to terminals located at an outer peripheral portion of a cell as well as a center of the cell. The center of the cell may increase a data transmission rate by supporting an additional antenna port by cells. However, since the outer peripheral portion of the cell may be significantly interfered with a peripheral cell, it may be difficult to increase the data rate greater than a certain limit without cooperation between cells. Further, in order for a user to provide a data service having a high rate in a dense zone, a reuse technology of a frequency through a small cell such as a Pico cell or a Femto cell in a zone of a Macro cell is supplied so that a requirement of a method of efficiently interference between transmission points has been increased.
A 3GPP provides a Coordinated Multi-Point transmission and reception (CoMP) scheme as a method of controlling the above interference. According to the CoMP, since the terminal simultaneously receives data through a Transmission Point (TP) such as a plurality of base stations or a plurality of antennas or receives the data from the best TP, a better service may be provided to the terminal. In order to provide the better service through the CoMP, uplink and downlink reference signals, channel state information of the terminal, a control channel structure, and a method of controlling uplink power have been continuously discussed.